1. Field of Invention
This invention relates to recoil reducing buffering (or attenuating) devices for firearm (employing an explosive charge) guns of various types, sizes, and degrees of automation; and more specifically, it relates to those types of counter-recoil apparatus employing a pneumatic-cylinder as its primary kinetic-energy absorption mechanism for both reducing mechanical-shock to the gun-structure, and to improve aiming-accuracy by reduction of “aim throw-off” imposed by each firing kick-back; -also, the disclosure sets forth features to provide improved projectile powering means applicable to air-guns.
2. Relevant Prior-Art
Background research discovery provides some prior patent-art regarded as germane to this disclosure, chronologically for example U.S. Pat. No. 836,502 (filed April 1906) shows a portion of an early automated firearm breech employing a buillt-in air-chamber fitted with an annular plunger-piston acting against a recoil-spring while engaged forwardly by a rearwardly recoiling-rod member of the breech mechanism.
In U.S. Pat. No. 900,865(Filed: May 1907) is shown an automatic magazine-fed handgun having a built-in air-chamber fitted with a plunger-piston, whereby the tubular air-chamber reacts aftward around the plunger-piston.
In U.S. Pat. No. 1,297,240(Filed: December 1916) is shown an automatic machine-gun having a built-in air-chamber fitted with a plunger-piston, whereby rearward action of the breech-bolt is rebuffed via both a recoil-spring and the momentary compression of captive air which reactively induced compression is regulatable via an adjustable screw-adjusted relief-valve device.
In U.S. Pat. No. 1,398,452(Filed: September 1919) is shown an automatic-rifle having an aftwardly built-in air-chamber and breech-piston arrangement obviating need of a recoil-spring.
In U.S. Pat. No. 1,351,141(Filed: April 1920) is shown a hydraulic (oil filled) recoil-buffer spool device for automated firearms, wherein a restricting orifice is staged between two longitudinally opposite chambers; and whereby a discharge of breech pressurized oil is forced past a preferably tapered longitudinal needle-valve arranged coaxially within said orifice. The arrangement in combination with a substantially conventional recoil-spring thus serving to modulate the otherwise jolt of sliding-bolt action upon firing of the gun.
In U.S. Pat. No. 3,298,282(Filed: February 1965 from Germany) is shown a built-in pneumatic recoil modulator device in combination with a conventional recoil-spring for automatic type firearms, wherein a fixed full-area piston is driven within an aftwardly traveling tubular breech extension chamber; the piston thus acting in concert with the helical-spring to more smoothly arrest aftward travel of the breech-bolt.
In U.S. Pat. No. 3,636,813(Filed: June 1969 from Germany) is shown an elaborate dual-cylinder hydraulic counter-recoil device employing full-area pistons acting within a pair of tubular barrels: which apparatus is intended for modulating the inertia-forces of recoil encountered in relatively heavy artillery weaponry, thus unsuitable for hand-portable guns.
In U.S. Pat. No. 3,599,530(Filed: November 1969) is shown an elaborate said automatic-replentisher for the hydro-pneumatic recoil systems of relatively large caliber weaponry; unsuitable for hand-portable guns.
In U.S. Pat. No. 3,901,125(Filed: March 1973) is exemplified an automatic-pistol of the popular Colt/45-caliber sidearm type, wherein is provided a combination conventional recoil-spring and a fixed delayed-action pneumatic-chamber driven over-upon by an aftward moving cupped front breech-plug (92), whereupon piston 102 (having an O-ring seal) ensues to build-up a compressive resistance to the recoiling breech inertia. The inventor teaches that the greater breach-loading sustained by the higher recoil-resistance, enables the sent projectile to travel further down the barrel before the bolt opens, allegedly improving aiming accuracy and repeated firing comfort owing to reduced “kick”. The pneumatic members are at ambient-pressure (not pre-pressurized) prior to firing, and a resilient rubber-cushion (132) is required to absorb final travel; —some contemplation is given to a retrofitable pneumatic device adaptable to such an older gun (col.-3/lines:4-15).
In U.S. Pat. Nos. 4,307,653(Filed: September 1979) and 4,445,644(Filed: May 1981) are shown generic variants of a recoil buffer with interacting first and second gas-chambers (note: neither of which is pre-pressurized, and some iterations include an oil medium), wherein upon recoil after firing, a compressive force is applied to the first chamber, whereby a gas/pressure-differential is generated between first and second longitudinal chambers, thus producing a gas flow into the second chamber via a venting fluid-diode restrictor device; hence, the apparatus is a type of shock-absorber only, still requiring a conventional metal recoil-spring for cyclic-action.
In U.S. Pat. No. 4,388,855(Filed: October 1980) is shown a built-in pneumatic decelerator device for a firearm, wherein a breech air-chamber (8, not pre-pressurized) also contains a metal recoil-spring (60) and is moved aftwardly upon firing of the gun, causing fixed hollow piston member (12) to effectively slide into the air-chamber, thus compressing both the spring and the air captive therein.
In U.S. Pat. No. 4,492,050(Filed: April 1983 from U.K.) is shown an air-powered gun having a gas-tight pressure-chamber for launching a projectile, which chamber is pressurized via a manually-actuated cocking-pump, and has no relevance to combating recoil action.
In U.S. Pat. Nos. 4,850,329 & 5,193,517 (Filed: February 1988 & June 1991) from U.K. by the Theoben-group; is shown a firing-mechanism for air-powered guns, wherein a longitudinal cylinder (4) with an internally sliding primary-piston (5) having an extended-skirt portion also contains a free-sliding bobbin-piston (1) acting as an inertial-mass within the extended-skirt; said bobbin-piston having an axial air-port and an optional coil-spring urging bobbin-piston toward the gun's discharge-port, the effect of which is to reduce accuracy disturbing kinetic-energy at the end of the primary-piston's projectile launching travel.
In U.S. Pat. No. 5,076,139(Filed: August 1990) is shown an exemplified conventional semi-automatic Beretta(mfg.) side-arm gun said to have a problematical hammering condition of the slide against the frame at maximum slide-travel, which creates destructing structural cracks in the frame. A resilient shim-like buffer device is thus retrofitable, which is said to significantly relieve the peak-loads imposed upon the frame: however, the simple device only treats the symptom, and does not eliminate the inherent mechanical defect inherent in this metal recoil-spring design.
In U.S. Pat. No. 5,265,852(Filed: October 1991) is shown a gas-spring of the type employed widely in the tooling-industry to reduce shock-forces encountered during mating of metal-dies: and noteworthy here is the use of a rod-like piston member, which owing to it's reduced piston-area relative to the cylinder-bore cross-section, is able to travel within the cylinder without creating excessive increase in internal working-pressure (as compared to a full-area piston operating within a closed cylinder).
In U.S. Pat. No. 5,339,789(Filed: July 1992 from Germany) is shown a low-recoil air-rifle, whereto the gun-mechanism referenced by the gun-barrel/breech (20) is mounted atop a wooden-stock portion (26), whereto a special mounting is provided between the gun-barrel and the gun-stock, which employs a roller and inclined-ramp mechanism serving to alter the vector of recoil-forces sufficiently as to greatly reduce loss of target in the sights upon firing of the air-rifle. However, such an extensive alteration to conventional existing guns is not a prectical consideration.
In U.S. Pat. No. 5,513,730(Filed: September 1995) is shown a so-called non-linear longitudinal recoil/shock-absorber apparatus for mounting abaxially to a gun-barrel for example, so as to react in a manner said to reduce recoil kick upon firing of the gun. A specially configured helical-spring is located inside the cylinderical body of the shock-absorber, which becomes axially torqued as to cause the spring to diametrically expand and impinge frictionally against the internal-wall of the cylinder chamber containing oil. However, it is believed that after extended use, the level of shock-absorption deteriorates owing to internal wear.
In U.S. Pat. No. 5,727,286(Filed: March 1996 from Taiwan) is shown a pneumatic door-closer of the elongate cylinder type, having an adjustable/needle-valve at the otherwise occluded end of the cylinder, and a piston-shaft extending oppositely from the cylinder. However, the internal piston-head is of the full-area type, and the primary feature of the invention is a two-stage linear-action loading, whereby internal-steps upon both the cylinder-wall and the piston-shaft facilitates a convenient “hold-extended” function, until the user applies an overcomming retraction force, whereby the piston-shaft is biased back inward of the cylinder.
In U.S. Pat. No. 5,797,593(Filed: December 1996 from Japan) is shown an oil-dampened cylindrical so-called gas-spring apparatus common to modern automotive use as a hatch-strut, which is referenced here primarily owing to its pre-pressurized factory-sealed swedged-over non-rechargable O-ring construction.
In U.S. Pat. No. 6,059,273(Filed: February 1995 from Sweden) is shown a cylinderical gas-spring having a full-area piston-head designed to provide relatively light initial longitudinal axial/thrust-resistance of the outwardly extending piston-shaft (4), and includes a cooperating donut-piston sliding internally on the piston-shaft, whereby greater resistance is provided once the piston-shaft has receeded slightly into the cylinder: this variable resistance action being facilitated via the internal gas-pressure/differential being impossed upon the full piston face versus the piston's partial opposite-side surface-area.
Therefore, in full consideration of the preceding patent review, there is determined a need for an improved form of device to which these patents have been largely addressed. The instant inventor hereof believes their newly improved firearm recoil pneumatic modulator device, commercially referred to as the RECOILX-Cartridge™, currently being developed for production under auspices of the Bergstrom-Mfg./Mkt.Co., exhibits certain advantages as shall be revealed in the subsequent portion of this instant disclosure.